The present invention relates to powered torque tools for applying torque to threaded fastening structures, such as threaded nuts and bolts. Powered torque tools conventionally include a drive motor drivingly connected to a gear train which in turn applies torque to a fastener through an engaging element such as a socket, tool bit, etc.
In the past a drive motor located in a cylindrical motor housing and a gear train located in a cylindrical gear housing have been coaxially connected together in operative engagement in a main housing. These forms of assembly frequently required costly threaded joints, splines, packing nuts and the like in order to connect the motor and gear housings while properly aligning and maintaining a desired driving engagement between the drive motor and gear train. One of the problems, however, is that such torque tools are constantly subject to vibrational and other loads which tend to loosen the connection between the housings and the alignment between the drive motor and gear train. This can lead to substantial wear of the engaged components, loss of efficiency and eventual failure.
The present invention is directed to a unique assembly structure and method which essentially eliminates such problems.
Here the present invention utilizes an assembly with a construction to slide a gear housing and a motor housing into a main housing and resiliently preload the gear and motor housings axially together with a spring structure such as disc springs. This can be done using a fixture to press the gear housing against the spring structure and in resilient engagement with the motor housing in the main housing. The preload is obtained and fixed when a set of openings or slots in the gear train housing align with a mating set of holes or openings in the main housing. At this point a matching pair of pins are simply installed through the aligned openings and the force for assembly is released. The pins can now retain a desired preload, such as approximately 800 pounds of tension, keeping the motor and gear housings resiliently connected together in the main housing.
In addition to keeping assembly and part costs to a minimum, this type of construction inherently provides desired concentricity and alignment between the motor and gear train and substantially eliminates chances for the housing connections to loosen, unscrew or otherwise deteriorate during operation.
At the same time the relatively simple construction facilitates disassembly for routine maintenance.
Therefore, it is an object of the present invention to provide a powered torque tool assembly with a unique construction in which drive motor and gear train housings are coaxially maintained connected in a main housing under a preselected resilient preload maintaining a desired alignment and engagement between the drive motor and gear train.
It is another object of the present invention to provide a torque tool assembly having a unique construction in which a drive motor housing and gear train housing are assembled and engaged under a preselected resilient preload by a fixed, non-rotatable connection.
It is still another object of the present invention to provide a torque tool assembly having a unique, simple construction in which a drive motor housing and gear train housing are held in engagement under a preselected resilient preload by a non-rotating locking mechanism whereby the engagement and alignment between the drive motor and gear train are maintained.
It is another object to provide a unique torque tool assembly with a unique construction for maintaining a drive motor housing and gear train housing in operative engagement under a preselected preload while inhibiting loosening and loss of preload.